Tudor 7021/0 - questions for the experts

[achova]

Have come across an odd one - a blue snowflake Tudor Submariner 7021/0 with excellent dial; hands (with appropriate residual tritium glow); case with correct lugs, nice chamfer, and engraving quality I'm accustomed to; clean movement in unusually nice shape with correct roulette wheel - serial 2484. I received it on a Rolex C+I rivet bracelet.

Now the questions about a couple elements which fall outside the norm. Most significantly, the 9542XX serial number is far outside the range published for this reference dating this to approximately 1980. I know Tudor serial dating have a wider tolerance but there are others oddities:

• Case back has no date stamp
• case back not as crisp or nicely finished as expected
• case does not have STAINLESS STEEL marking
• unusual pen marking on inside of lug - would not expect to make it out of quality control
• bezel insert more matte finish than expected

Possible conclusions?

1) Offered on a special basis to some markets / agency
2) Service-replacement case
3) franken?

Like to hear thoughts from the Tudor experts out there - Morgan - Orchi - other Adam?

Thanks!